FREMONT — Two Oakland detectives driving an unmarked police car led the foster father of missing 5-year-old Hassani Campbell away from his home Friday for additional questioning.

The two investigators were at Louis Ross’ home on Roxie Terrance in Fremont on Friday afternoon, and at about 1:30 p.m., the officers exited the home and waited at their vehicle, which was half-parked on the sidewalk.

A few minutes later, Ross emerged from his family’s two-story home wearing a light-colored dress shirt and dark-colored pants.

He walked swiftly across the lawn and got into the back seat of the police vehicle. The car then drove off.

Friday’s visit with Ross was a routine part of the investigation, police said. The lead homicide investigator assigned to the case had not previously spoken directly with Hassani’s foster father and wanted to get up to speed. Ross was not taken to the police station.

Ross, 38, is the last person to reportedly see Hassani before he disappeared Monday from behind a shoe store in Oakland’s Rockridge neighborhood, where Ross was dropping off Hassani and his 1-year-old sister with his fiancee, Jennifer Campbell.

Ross earlier this week took a polygraph test, reportedly administered by the FBI, but the results have not been released.

Police have been investigating Hassani’s disappearance as a missing persons case, but have called in homicide investigators for assistance.

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